Reversible rachet wrenches are well known. While there are numerous different designs, a typical reversible rachet wrench includes a head portion and a handle portion. Mounted in the head portion is a toothed rachet wheel and a socket pin. The head also includes a pivotal pawl element or member and a mechanism to pivot the pawl element from a first position (where the rachet wheel rotates in a clockwise direction) to a second position (where the rachet wheel rotates in a counterclockwise direction).
The mechanisms for effecting reversal of the direction of the rachet wheel are quite varied. Perhaps the most common mechanism is illustrated in FIGS. 1 and 2 of U.S. Pat. No. 5,761,972 to J. A. Sanders. The direction reversal mechanism includes a two position pawl 27 which engages rachet wheel 18 (referred to as a spur gear) for rotating of the socket pin 16 in either a clockwise or counterclockwise direction. The pawl assembly includes a pawl lever 24 connected, via shaft 26, to the pawl 27 for switching, as desired by the user, between engagement for clockwise or counterclockwise rotation of the rachet wheel and socket pin. Sanders also includes an advancing lever 30, extending from a slot in the side of handle 14 for "finger" tightening or loosening.
U.S. Pat. No. 4,254,675 to Marlow et al., discloses a reversible rachet wench which includes a head portion, a handle portion 14, a toothed rachet wheel 24 and a pawl element 34. Reversal of the direction of pawl 34 is effected by a mechanism that includes a control rod 52 having an enlarged end 54 with an offset bore 58 (in which is received spring 60 and pawl engaging pin 62). The opposite end of rod 52 is connected to barrel 70 via cap 78. When it is desired to reverse the rotational direction of rachet wheel 24, the operator merely pushes barrel 70 toward the head until a detent enters notch 64, and then rotates barrel 70 in either a clockwise or counterclockwise direction. As barrel 70 rotates so does control rod 52 and pin 62. Since the pin is eccentrically mounted, it rides up or down the engaged cam surface (98 or 100) of pawl element 34 until it reaches junction 102. Continued rotation of barrel 70 moves the pin past the junction and as it does spring 60 releases its energy and forces pin 62 outwardly against the newly engaged cam surface and forces the pawl element 34 to rotate quickly to engage the other pawl member 84, 86 with the wheel 24, thereby permitting rotation of the rachet wheel in the direction opposite of the initial direction and preventing rotation in the initial direction.
Other direction reversing mechanisms are illustrated in U.S. Pat. No. 4,869,138 (J. L. Ferris), U.S. Pat. No. 4,967,624 (J. L. Ferris), U.S. Pat. No. 4,274,311 (E. Ebert), U.S. Pat. No. 3,659,484 (G. L. Scodeller), U.S. Pat. No. 4,457,107 (S. Waiser), U.S. Pat. No. 5,582,080 (T. C. Barmore), U.S. Pat. No. 5,957,008 (P. S. Long), and U.S. Pat. No. 4,631,990 (M. E. Hughes). All the foregoing suffer from the drawback that they include numerous parts, all of which increases manufacturing costs and reduces reliability.